1. Field of the Invention
The present invention relates to a turbocharger for a gas operated internal combustion engine in which air and gas are fed to the compressor.
2. Description of the Related Art
In the known arrangements of this type, the gas is fed to the air upstream of the turbocharger. To this end, a venturi tube is connected in-line between a silencer and the compressor. Holes are provided in the narrowest cross section of this venturi tube. The gas flows into the venturi tube through these holes. The flow is accelerated in the venturi tube and a vacuum is thus created for gas admixing.
A disadvantage of this is that a relatively long line has to be provided between the silencer and the compressor. A further disadvantage is that the air in the venturi tube is first accelerated and subsequently decelerated again in order to then be accelerated again at the outlet of the compressor wheel. This leads to pressure losses upstream of the compressor. As a result, the air mass flow rate and the charge pressure decrease.
The object of the invention is to provide a simple arrangement of compact construction for introducing gas into the air in a turbocharger.
According to the present invention, this object is achieved by an arrangement including gas passage openings being provided in an air intake connection of a compressor.
While dispensing with a venturi tube, an existing component can be used for the gas feed, a factor which results in a simple and compact arrangement. In this case, the accelerating flow of the air upstream of the entry to the compressor impeller is advantageously utilized for drawing and admixing the gas. Compared with the known arrangement, this results in lower pressure losses upstream of the compressor, and gives rise to a higher charge pressure and a greater air mass flow rate. In addition, depending on the position of the gas passage openings, a higher vacuum can be achieved for the gas admixing. A silencer is provided in the intake path of the air. The silencer may be fastened directly to the housing of the compressor.
In a particularly preferred embodiment, the gas passage openings are arranged in the region of the smallest diameter of the air intake connection.
An annular collecting space intended for the gas is provided on the outside with an inlet connection. Preferably, the annular collecting space is formed between the air intake connection and the outflow housing of the compressor. In this arrangement, a supporting wall, which is generally present anyway, for the outflow duct of the compressor, may be used for forming the collecting space. Therefore, no additional components are required for providing the collecting space.
In a further embodiment of the invention, the gas passage openings between the air intake connection and the collecting space are arranged so as to be uniformly distributed over the circumference of the air intake connection. This results in uniform mixing of the gas with the air.
A silencer is expediently connected directly to the air intake connection of the compressor. This promotes the compact construction of the arrangement.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.